“Digital wrapper” frames, as described in ITU-T Recommendation G.709/Y.1331 (International Telecommunication Union, February 2001), are intended to be transferred over optical links with bit rates of up to 10 Gigabits/second (Gbps). Each Digital Wrapper frame contains 16,320 bytes, only six of which are devoted to frame synchronization. In practical applications, electrical switching and/or routing equipment (such as serial backplanes) must transmit digital wrapper frame data using relatively low bandwidth electrical channels. For example, it may be desirable to transmit digital wrapper frame data over four 2.5 Gbps channels supported by a serial backplane interface. In view of the limited number of frame alignment bytes contained in each digital wrapper frame, the digital wrapper frame data cannot be simply divided for transmission over four channels—the individual channels will not be able to synchronize using only six frame alignment bytes.
One known technique provides framing for serial backplane lines transmitting digital wrapper frame data by replacing some of the forward error correction parity bytes within the digital wrapper frames with frame alignment bytes. Using this technique, each of the serial backplane channels is provided with a number of frame alignment bytes sufficient to establish synchronization. The cost of this frame alignment technique is the loss of forward error correction parity information and, consequently, increased data transmission errors.